Retrospective Analysis of Outcome in GIST patients on Imatinib in Sarawak General Hospital: A Single Institution Experience

Date 24 November 2018
Event ESMO Asia 2018 Congress
Session Poster display - Cocktail
Topics Anticancer Agents
GIST
Personalised/Precision Medicine
Presenter Ying Ying Sum
Citation Annals of Oncology (2018) 29 (suppl_9): ix28-ix45. 10.1093/annonc/mdy431
Authors Y.Y. Sum1, U. Nagaswara1, S.K. Kho1, C.J. Lim2, Y. Junie Khoo1
  • 1Radiotherapy And Oncology, Sarawak General Hospital, 93586 - Kuching/MY
  • 2Clinical Research Centre, Sarawak General Hospital, 93586 - Kuching/MY

Abstract

Background

Gastrointestinal stromal tumours (GISTs) are the commonest mesenchymal tumours in the gastrointestinal tract. A paradigm of molecularly targeted therapy in GISTs made imatiniban effective therapy. This study aims to analyse treatment outcomes of GIST patients treated with imatinib in Sarawak General Hospital (SGH) and todetermine prognostic factors associated with survivals.

Methods

Fifty patients diagnosed with GIST for treatment with imatinib were included in this retrospective study. Patient data were retrieved from clinic records, pharmacy census and GIST patient database.

Results

In our cohort, male predominance was observed (60%) with mean age of 57.7 years old. The commonest primary site is stomach (48%) followed by small bowel (24%).70% patients are diagnosed as advanced GIST, metastasis seen primarily in the liver (68.6%). Imatinib dose adjustment was required in 14 (28%) patients, 64.3% due to disease progression and 35.7% due to toxicity. Anaemia (36%) is the commonest reported side effect followed by skin toxicity (20%) and neutropenia (16%). The median survivalfor patients was 301.21 days using Kaplan Meier analysis whereas median progression free survival was 105 days. Log Rank test for survival of different treatment post progression showed significant difference in survival between imatinib dose escalation versus best supportive care(X2 statistics: 4.263; p = 0.039).However, no significant difference wasseen between imatinib dose escalations versus second line Sunitinib(X2 statistics: 1.471; p = 0.225). The table illustrates prognostic factors associated with survival using Simple Cox Regression.Table: 116P

VariablesHR (95% CI)P value
Age0.964 (0.903, 1.029)0.271
Gender Female Male1.00 1.183 (0.290, 4.827)0.814
ECOG4.071 (0.725, 22.879)0.111
Size 5-10CM >10CM1.00 0.408 (0.084, 1.987)0.267
Distant Metastasis No Yes1.00 2.327(0.272,19.889)0.440
Mitotic Index (MI/50hpf) <5 >101.00 2.035 (0.364, 11.390)0.419

Conclusions

From our study, we conclude that poor ECOG, high mitotic index and advanced GIST carry higher risk to death numerically. Imatinib dose escalation upon progression has significantly better survival compared to best supportive care.

Editorial acknowledgement

Clinical trial identification

NMRR ID 40174.

Legal entity responsible for the study

MREC/NMRR Malaysia.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.